Stratigraphic Framework of the Wolfcamp – Spraberry of the Midland Basin Roswell Geologic Society October 8, 2019 Lowell Waite Department of Geosciences Permian Basin Research Lab University of Texas at Dallas Permian Basin Research Lab at UT Dallas Dr. Robert J. Stern and Mr. Lowell Waite, Co-Directors -- established January, 2019 -- Goals: • Advance understanding of all geologic aspects of the Permian Basin through open applied research, linking academia and industry • Educate and better prepare students for professional careers in the oil and gas industry • Graduate courses offered: • Geology of the Permian Basin • Petroleum Geoscience • Paleo Earth Systems: Global Themes https://labs.utdallas.edu/permianbasinresearch/ Stratigraphic framework of Wolfcamp – Spraberry: Objectives • Review the tectono-stratigraphic framework of the Wolfcamp and Spraberry deep-water units of the Midland Basin, west Texas • Briefly discuss the facies/characteristics of these rocks • Highlight the differences between the Wolfcamp shale (A – D) and Spraberry depositional systems Note: although not specifically addressed, the framework outlined here is applicable to the Delaware Basin Greater Permian Basin Region • Confluence of Marathon- Ouachita fold and thrust belt and Ancestral Rockies basement-involved uplifts (Penn. – early Permian) Study Area Precursor Tobosa Basin (Ord. to Miss.) Fold and thrust belt Basement uplift Shallow marine shelf Reef / shoal complex Deep marine basin Permian Basin Stratigraphy and Tectonic History Ma System Series Delaware Basin CBP & NW Shelf Midland Basin Tectonic Phase 252 Formations Formations Formations Dewey Lake Dewey Lake Dewey Lake Rustler Rustler Rustler final basin fill/termination Ochoan Salado Salado Salado Castile Lamar Tansill Tansill Mtn Yates Yates Bell Canyon Seven Rivers Seven Rivers Post Orogenic Loading Capitan Guadalupian Queen Queen Group Cherry Canyon Rapid Subsidence; Seep Permian Goat Grayburg Grayburg Delaware Delaware Upper San Andres Onset of HC Generation Brushy Canyon San Andres Lower San Andres Cutoff Member / Clear- 1st Carb / Avalon Holt / Upr Leonard Holt /Upper Leonard Lwr San Andres fork ( ~ 50 million yrs. duration ) Bone 1st Sand Glorieta Upper 2nd Carb Middle 2nd Sand Upper Clearfork Spraberry Leonardian Spring Yeso / Lwr Jo Mill 3rd Carb Stray Sd Middle Clearfork L. SPBY Sh Clearfork 3rd Sand Tubb Dean Lower Clearfork Wichita / Abo Wolfcamp A Wolfcamp Wolfcamp Wolfcamp B Wolfcampian Wolfcamp Wolfcamp C1 mid – Wolfcamp unconformity 299 Wolfcamp C2 Early WFMP Event ActiveMargin Virgilian Cisco Cisco Cisco Wolfcamp D Penn. – Early Permian Missourian Canyon Canyon Canyon Foreland Deformation Desmoinesian Strawn Lime Strawn Lime Strawn Lime Pennsylvanian Detrital Detrital Detrital Strawn Event PERMIAN BASIN PHASE Bend Lm (~ 30 million yrs. Atokan Atoka Atoka Atoka Sh & Detrital Atokan Event Morrowan Morrow Morrow (NW Shelf Only) Morrow Morrow Event duration) 323 Chesterian U. Miss Lm U. Barnett U. Miss Lm U. Barnett Barnett L. Barnett L. Barnett Meramecian – Mississippian Osagean L. Miss Lm L. Miss Lm L. Miss Lm Kinderhookian 359 Woodford Woodford Woodford Upper Tobosa Basin Devonian Middle (Middle Ordovician to Lower Devonian (Thirtyone) Devonian (Thirtyone) Devonian (Thirtyone) 419 Late Mississippian) U. Niagaran Upper Silurian (Wristen) Upper Silurian (Wristen) Upper Silurian (Wristen) Moderate Subsidence Silurian L. Niagaran Fusselman Fusselman Fusselman Alexandrian (~ 150 million yrs. duration) 444 Cincinnatian Montoya Montoya Montoya Sylvan Sh. Mohawkian Bromide Bromide Bromide Tulip Crk. Tulip Crk. Tulip Crk. McKee Sd. McKee Sd. McKee Sd. Mclish Mclish Mclish Waddell Sd. Waddell Sd. Waddell Sd. Chazyan Oil Creek Oil Creek Oil Creek TOBOSA PHASE BASIN TOBOSA Ordovician Connell Sd. Connell Sd. Connell Sd. PassiveMargin Simpson Simpson Simpson Joins Joins Joins Canadian Ellenburger Ellenburger Ellenburger Ozarkian Great American Carbonate Bank 485 Wilberns (Late Cambrian – Early Ordovician) Cambrian Upper Bliss Absent Bliss / Hickory / Riley 541 Basement assembly and breakup of (modified from Precambrian Precambrian Precambrian Precambrian Basement Basement Basement Rodinia supercontinent Reed, unpub., 2016) Grenville Orogeny (1.3 to 1.0 bya) Guadalupe Central Mountains Delaware Basin Basin Midland Basin Eastern Shelf Platform Ft. +5,000 Triassic Salado Dewey Lake datum: sea level 0 Queen - Grayburg Tansill – Yates – Seven Rivers Clear Fork Wichita - Abo -5,000 Woodford Strawn - Atoka Woodford -10,000 -15,000 (WTGS,( 1984) -20,000 Ft. +5000 Midland Basin 0 Delaware Basin -5000 -10000 -15000 The Permian Basin -20000 Top Precambrian structure (courtesy of Mark George, PXD) -25000 LATE PENNSYLVANIAN – EARLY PERMIAN EVOLUTION OF WESTERN PANGEA Late Pennsylvanian • Icehouse climate; PB in humid-tropical setting (abundant rainfall) • Numerous high-freq., high-amplitude sea-level changes • Expansion of Penn seaway (long-term rise); stratified water columns • Continued tectonism in west Texas (Marathon-Ouachita FTB, rise of ARM) A very dynamic time in Earth history, especially in west Texas Wolfcampian – Early Leonardian • Waning icehouse, transition to greenhouse • Northward drift of Pangea • Increasing aridity & expansion of continental desert in western U.S. • Cratonic emergence / contraction of seaway (onset of long-term SL fall) (maps: Ron Blakey, NAU/Colorado • Culmination of tectonic pulses in W. TX (mid WC); Pacific arc volcanism (Late WC-Leon.); Plateau Geosystems) PB enters rapid subsidence phase (Dean - Spraberry) Chrono- Sea-level 2nd-order Operational stratigraphy rise cycles FZ Units a. b. c. Stratigraphic framework, 5 FZ. Fusulinid zonation Wolfcamp - Spraberry T a. Tectonic R Greenhouse pulses 4 b. Ash beds rd T Numerous 3 - and higher-order c. Climate phase cycles of sea-level change R organized into larger 2nd-order 3 trends (5 – 10+ m.y. in duration); T R from oldest to youngest: mwu mwu: mid-Wolfcamp 2 unconformity 1 WC D – lowermost WC C2 T 2 WC C2 3 WC C1 R = Regression 4 WC A - B R T = Transgression 5 Spraberry – L. Clear Fork 1 (Sea-level curve from T Ross and Ross, 2009; Fusulinid zonation from Wahlman, 2019) Midland Basin Type Log MD (ft.) Strati- graphy GENERAL DESCRIPTION / DEPOSITIONAL FACIES 7500 Upper Leonard Upper Spraberry 8000 Middle Spraberry Spraberry – Dean: silty mudstones and clay-rich siltstones punctuated by Lower multiple deeper-water submarine fan complexes Spraberry 8500 Jo Mill (incl. massive to laminated, fine-grained sandstones) Lower Leonard Shale Leonardian 9000 Dean A Wolfcamp A – B: 9500 silty- and calcareous organic-rich mudstones; - B carbonate percentage increases upward C1 ian mid-WC Wolfcamp C: Clay-rich shale unconformity Wolfcamp 10000 C2 Wolfcamp (progradation of Eastern Shelf deltas & Glasscock Nose) WFMP D Wolfcamp D: Basinal cyclothems (starved basin) 10500 Penn. Lower Strawn: shallow-water platform limestones (modified from Hamlin and Baumgardner, 2012) Lower Strawn Limestone and Wolfcamp D (Cline) STRAWN GROUP STRATIGRAPHY (DESMOINESIAN SERIES) Mid Continent / Anadarko Basin AAPG COSUNA chart (1985) Midland Basin Eastern Shelf Midland Basin Admiral Fm. Fusulinid zonation Wolf- Putnam Fm. camp- Wolfcamp Moran Fm. ian Formation Pueblo Fm. Virgil- Cisco – Cisco Gp. ian Canyon Miss- Group Canyon Gp. ourian Des- moine- Strawn Strawn Gp. sian Gp. Pennsylvanian Atokan Bend Gp. Bend Gp. Morro- wan (Reed and Mazzullo, 1987) Barnett Ches- terian Shale Mera- Lower Strawn Limestone = Early Strawn mec- Mississippian Mississippian ian Limestone Limestone Mississippian Middle & Upper Strawn = Osagean lower portion of WC D (Gianoutsos et al, USGS, 2014) Lower Desmoinesian Facies (Lower Strawn Limestone) • Shallow water platform carbonate facies extend across entire Midland Basin and Eastern Shelf region • Lower Strawn Limestone is generally < 200 ft. thick in Midland Basin • Core analyses indicate typical Penn shelf cyclothem deposits: burrowed skeletal wackestones grading upward into phylloid algal packstones and skeletal grainstones, capped by exposure surfaces • Pre-dates drowning of Midland, Delaware basins (Wright, 2011) Wolfcamp D (Canyon – Cisco) facies Photomicrographs of highly porous limestones of the Horseshoe Atoll reef complex (Saller et al., 1999) Organic-rich Wolfcamp D (Canyon – Cisco) black shales in core from the center of Midland Basin • Drowning of basins and backstepping of surrounding shelfal regions (Ewing, 2016) 2 in. Wolfcamp D: Basinal cyclothems • Equivalent to classic “Penn. cyclothems” on shelves • Silica – rich shales; relatively high clay content R • Each basinal cyclothem = 15 – 45 ft. thick; bounded by 1 thin dolomite or LS; highly correlative basin-wide • Organic content partitioned into multiple thin cycles T • High pore pressures due to depth, maturity Res. 0 GR 150 0.2 2000 10400 D 10500 Wolfcamp non-porous, thin dolomite or LS organic-rich, silica-rich shale 100 ft. clay-rich, low TOC shale 10600 L. Strawn Wolfcamp C Wolfcamp C Preliminary correlation of MB tops to Eastern Shelf • Westward progradation of Eastern Shelf delta systems and platform margins (100 -150 km) • Initial development of Glasscock Nose during WFMP C1 time • (Sinclair et al., 2018) Uplift of CBP structural blocks and development of mid-Wolfcamp unconformity Progradation of Wolfcamp C shelf delta systems across the Eastern Shelf Sequential development of the Glasscock Nose prograding, mounded deep-water carb. flows (Sinclair et al., 2017) SW (Sinclair et al., 2017) Possible analog: carbonate delta drift Indian Ocean/Maldives